Environmental changes significantly alter the structure,diversity and activity of soil microbial communities during spring freezing-thawing period,leading to changes in the soil microbial nitrogen cycle.Changes in N_(...Environmental changes significantly alter the structure,diversity and activity of soil microbial communities during spring freezing-thawing period,leading to changes in the soil microbial nitrogen cycle.Changes in N_(2)O fluxes after land use conversion from primary forest to secondary forest,Korean pine plantation and cropland in northeast China have not been quantified.Field experiments were conducted to measure soil N_(2)O fluxes in a primary forest,two secondary forests,a Korean pine plantation,and one maize field in a temperate region in northeast China from 2017-03-06 to 2017-05-28.During the experimental period,the soil was exclusively a nitrogen source for all land uses.We found that N_(2)O emissions ranged from 15.63 to 68.74μg m^(-2) h^(-1),and cumulative N_(2)O emissions ranged from 0.33 to 2.10 kg ha^(-1) during the period.Cumulative N_(2)O emissions from the maize field were significantly higher than that from primary forest,Korean pine plantation,hardwood forest,and Betula platyphylla forest by 262.1% to 536.4%.Compared with other ecosystems in similar studies,the N_(2)O emission rates of all ecosystem types in this study were low during the spring thaw period.Stepwise multiple linear regression indicated that there were significant correlations between N_(2)O emissions and environmental factors(air temperature and soil temperature,soil water content,soil p H,NH_(4)^(+)-N,NO_(3)^(-)-N,and soil organic carbon).The results showed that conversion of land use from primary forest to hardwood forest,Korean pine plantation or maize field greatly increased soil N_(2)O emissions during spring freezing-thawing period,and N_(2)O emissions from primary forest were almost the same as those from Betula platyphylla forest.展开更多
基金financial assistance and support from the Hubei Key Laboratory of Construction and Management in Hydropower Engineering,China Three Gorges University(No.2020KSD09)the National Key Research and Development Program of China(2017YFC0504102)+1 种基金the National Natural Science Foundation of China(51979147)the Ministry of Finance,the Ministry of Industry and Information Technology,and the Ministry of Science and Technology for support of the High Tech Zone in Yichang in creating a special project for highly talented research(No.B19-004)。
文摘Environmental changes significantly alter the structure,diversity and activity of soil microbial communities during spring freezing-thawing period,leading to changes in the soil microbial nitrogen cycle.Changes in N_(2)O fluxes after land use conversion from primary forest to secondary forest,Korean pine plantation and cropland in northeast China have not been quantified.Field experiments were conducted to measure soil N_(2)O fluxes in a primary forest,two secondary forests,a Korean pine plantation,and one maize field in a temperate region in northeast China from 2017-03-06 to 2017-05-28.During the experimental period,the soil was exclusively a nitrogen source for all land uses.We found that N_(2)O emissions ranged from 15.63 to 68.74μg m^(-2) h^(-1),and cumulative N_(2)O emissions ranged from 0.33 to 2.10 kg ha^(-1) during the period.Cumulative N_(2)O emissions from the maize field were significantly higher than that from primary forest,Korean pine plantation,hardwood forest,and Betula platyphylla forest by 262.1% to 536.4%.Compared with other ecosystems in similar studies,the N_(2)O emission rates of all ecosystem types in this study were low during the spring thaw period.Stepwise multiple linear regression indicated that there were significant correlations between N_(2)O emissions and environmental factors(air temperature and soil temperature,soil water content,soil p H,NH_(4)^(+)-N,NO_(3)^(-)-N,and soil organic carbon).The results showed that conversion of land use from primary forest to hardwood forest,Korean pine plantation or maize field greatly increased soil N_(2)O emissions during spring freezing-thawing period,and N_(2)O emissions from primary forest were almost the same as those from Betula platyphylla forest.
